2-Phenylpyridines I ##STR1## wherein X is a chemical bond, 1,2-ethynediyl or optionally substituted --(CH.sub.2).sub.1-3 --, --O--(CH.sub.2).sub.1-2 --, --s--(CH.sub.2).sub.1-2 --, --CH.sub.2 --O--CH.sub.2 --, --CH.sub.2 --S--CH.sub.2 -- or --CH.dbd.CH--;Y is oxygen or sulfur;Z.sup.1 is oxygen, sulfur or --N(R.sup.7)--;Z.sup.2 is oxygen, sulfur or --N(R.sup.8)--;R.sup.1, R.sup.2, R.sup.7 and R.sup.8 independently of one another are hydrogen, optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, phenyl or heterocyclyl; orR.sup.1 and R.sup.2 or R.sup.7, or R.sup.2 and R.sup.8 together are optionally substituted --(CH.sub.2).sub.2-5 -- or --(CH.sub.2).sub.2 --O--(CH.sub.2).sub.2 --, orR.sup.1 and R.sup.2 together are optionally substituted 1,2-phenylene;R.sup.3 is cyano, halogen, alkyl, haloalkyl, alkoxy or haloalkoxy;R.sup.4 and R.sup.5 are hydrogen or halogen;R.sup.6 is halogen or haloalkyl;n is zero or one;and their salts are suitable for controlling undesirable vegetation and as desiccants or defoliants.